204 Smith and Butler . — Relation of 
growth of the plants in the full nutritive solution was twelve times larger 
than that of the plants grown in the absence of potassium. 
The distribution of potassium in the plants is shown in Table XV. It 
will be noticed that the plants growing in the absence of potassium were 
able to obtain 2 mg. potassium from the substratum, and therefore grew 
under less favourable conditions for showing the effect of absence of this 
element than did the wheat in Experiments i and 2. Nevertheless, the 
ratio of potassium distribution in stems and roots per gramme of dry matter 
formed is the same whether the plants are grown in the presence or absence 
of potassium, results which agree with those obtained in the case of wheat. 
The figures for the amount of potassium absorbed per gramme of dry matter 
formed are also substantially the same as those given by wheat. 
Table XVI. Green and dry weights of Early pedigree Dent field Corn 
grown 32 days in water cultures free from and containing potassium. 
Nutritive solution 
No . of 
Total weight of plants . 
Dry weight of 
Ratio of 
tops to 
used . 
Plants . 
Green . 
Dry . 
Tops . 
Roots . 
roots . 
Grin. 
Grm. 
Grm. 
Grm. 
Nutritive solution F 
3 
35-305 
3.9296 
2.7996 
1. 1 300 
3 
40-950 
4.2784 
3.0881 
1.1903 
3 
30-821 
3-5257 
2.5138 
1. 011 9 
3 
28.592 
3-3369 
2-2564 
1-0805 
Mean 
1 
11.306 
1-2559 
0-8882 
0.3677 
2-42 
Nutritive solution F, 
3 
2.480 
0.5067 
0.3720 
0.1356 
less potassium. 
3 
4-333 
0.7630 
0-5583 
0-2047 
3 
6.769 
0-9881 
0.7191 
0-2690 
3 
3-999 
0.7024 
0.5232 
0-1792 
Mean 
1 
L465 
0-2467 
0-1810 
0 0657 
2-75 
Experiment 4, In this experiment Early pedigree Dent field Corn was 
grown in water culture, solution F being used for the full nutritive solution, 
and without the addition of potassium for the solution less this element. 
Three corn plants were grown in each culture vessel, the jars used contain- 
ing i,6oo c.c. solution. The seed was transferred to the jars when the 
primary root was about a half-centimetre long, and before the epicotyl had 
broken through the coleoptilum. At the end of thirty-two days the plants 
in the solution from which potassium was absent had ceased growing and 
were practically dead, while those in the full nutritive solution were perfectly 
healthy and growing vigorously. The experiment was, therefore, brought 
to a close and the plants weighed and analysed. The total green and dry 
weights of the plants and the ratio of top growth to root growth arefgiven in 
Table XVI. The data presented show that the growth of the plants in the 
